This is the other face of the coin when it comes to the relationship between the main code and unit testing. Besides the pragmatic reasons explored in the previous section, it comes down to the fact that good software is testable software. Testability (the quality attribute that determines how easy to test software is) is not just a nice to have, but a driver for clean code.
Unit tests aren't just something complementary to the main code base, but rather something that has a direct impact and real influence on how the code is written. There are many levels of this, from the very beginning when we realize that the moment we want to add unit tests for some parts of our code, we have to change it (resulting ...
